MANUFACTURING RED BLOOD CELLS FROM STEM CELLS; FROM BENCH TO PHASE 1 CLINICAL TRIAL

• Published in: Cytotherapy (Oxford, England) England), 2024-06, Vol.26 (6), p.S92-S92
• Main Authors: Blair, A., Kupzig, S., Allen, R., Bruce, L., Bailey, C., Green, A., Cavagnetto, C., McFarlane, H., Mutenta, G., Hughes, E., McFeeters, O., Smythe, J.
• Format: Article
• Language: English
• Subjects: CD34; Phase 1; RBC
• ISSN: 1465-3249; 1477-2566
• DOI: 10.1016/j.jcyt.2024.03.174

Continued provision of life saving products for patients with blood disorders is an essential role of blood service organisations. However, there is often an unmet need for such products due to the difficulties in matching for multi-transfused patients. To help address this inequality, we developed a methodology to generate red blood cells (RBC) from human CD34+ peripheral blood cells. Using this system, we reported the greatest yield of enucleated cultured RBC to date. Furthermore, we demonstrated longer survival of ex vivo generated RBC following transfusion in murine models, compared to standard RBC. This is clinically significant, as ex vivo generated RBC will provide a cohort of younger cells compared to donated blood. Together with their longer survival and superior functional characteristics, these cells may reduce the number of transfusions required by patients with β-thalassemia or sickle cell disease. As a logical progression of this work, we are undertaking a first-in-human randomised controlled trial of ex vivo generated red blood cells. The RESTORE trial (ISRCTN42886452) compares survival of 51Cr labelled, manufactured (mRBC) with standard (sRBC), from the same healthy donor (age 18-28 years) in a healthy allogeneic recipient, in 10 donor recipient pairs. Reaching this point required significant technology transfer expertise to convert the established methodology to a GMP procedure that meets regulatory requirements. A considerable number of adaptions to the original methodology were required, including change of starting material, use of GMP compatible reagents, closed system processing and establishment of quality testing and release criteria. Validation of GMP mRBC in vivo demonstrated that they survived in the murine circulation longer than sRBC, even after storage for up to 10 days. The refined, regulator approved protocol generates mini-doses of enucleated mRBC over an 18 day period. To date, we have successfully generated the required doses of mRBC, with median pre-filtration enucleation rates of 68.1%, from 5 donors, irrespective of age or initial CD34+ cell count. This is the first allogenic trial of ex vivo generated RBC to be undertaken globally. It demonstrates in-house transfer of internationally acclaimed fundamental research to a clinical product manufactured by NHSBT Advanced Therapies Unit, with specialist quality and clinical trials stakeholders.